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91.
Received: 9 November 1998 / Accepted: 25 November 1998 相似文献
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Fabrice Domingues Dos Santos Pascale Fabre Xavier Drujon Gilles Meunier Ludwik Leibler 《Journal of Polymer Science.Polymer Physics》2000,38(23):2989-3000
Structured latexes provide a promising route to hard coatings without the use of coalescing aids. We studied the thermomechanical properties of films from structured soft‐core/hard‐shell hydrophobic latexes. We found that the mechanical properties of these films were closely related to their very particular organization. When the rigid phase was continuous, whatever its volume fraction, the films exhibited a high elastic modulus. An analysis of the viscoelastic properties of the films provided a good method for obtaining information about the interphase between the hard shell and soft core of the latex particles. By varying the film structure through annealing or the particle composition (core/shell ratio, core crosslinking, etc.), we were able to tune the mechanical properties of the films. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2989–3000, 2000 相似文献
94.
Judith C. Gallucci Sbastien Gentil Nadine Pirio Philippe Meunier Fabrice Gallou Leo A. Paquette 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):m67-m69
Transmetallation of the dilithium salt of (3,5‐dimethyphenylamino)(isodicyclopentadienyl)dimethylsilane by treatment with zirconium tetrachloride in a 2:1 ratio leads to the substitution of all four chloride ligands. With the applied stoichiometry, the title complex, [Zr(C20H25NSi)2]·C4H10O, was obtained and crystallized from diethyl ether. X‐ray diffraction characterization showed that both isodicyclopentadienyl ligands (alternatively called 4,5,6,7‐tetrahydro‐4,7‐methano‐1H‐indene) are complexed to the metal on their exo face in a completely stereoselective manner and that they are η5‐bonded to the Zr atom. 相似文献
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New metallocene dichlorides [η5-(1,4-Me2-2,3-Ph2-C5H)2TiCl2] (2), [η5-(1,4-Me2-2,3-Ph2-C5H)2ZrCl2] (3) and [η5-(1,4-Me2-2,3-Ph2-C5H)η5-(C5H5)ZrCl2] (4) were prepared from lithium salt of 1,4-dimethyl-2,3-diphenylcyclopentadiene (1) and [TiCl3(THF)3], [ZrCl4] and [η5-(C5H5)ZrCl3(DME)], respectively. Compounds 2-4 were characterized by NMR spectroscopy, EI-MS and IR spectroscopy, and the solid state structure of 3 was determined by single crystal X-ray crystallography. The catalytic systems 3/MAO and 4/MAO were almost inactive in polymerization of ethylene at 30-50 °C, however, they exhibited high activity at temperature 80 °C. The catalyst formed from 2 and excess of MAO was practically inactive at all temperatures. 相似文献
98.
Weimeng Ding Jean-Philippe Sylvestre Emmanuelle Bouvier Grégoire Leclair Michel Meunier 《Applied Physics A: Materials Science & Processing》2014,114(1):267-276
The laser fragmentation technique has been extensively used to produce inorganic nanoparticles, but its practice on organic materials, especially on drugs, is less common. Here, we briefly review the recent advances in laser micro-/nanonization of organic materials and the rationale of using laser fragmentation for drug discovery. We present our case studies of two drug models: fenofibrate and naproxen. Both drugs were fragmented in water with femtosecond (fs) laser and characterized in terms of particle size distribution and physicochemical properties. Effects of fs laser fragmentation were also compared with nanosecond (ns) laser fragmentation and with conventional media milling technique. Fs laser was more suitable to produce sub-micron size drug particles than ns laser, but degradation of drugs after nanonization was also more pronounced than micronization. Physicochemical transformations such as oxidation, hydration and amorphisation might occur during the laser–material interactions. Laser nanonization showed improved dissolution kinetics, similar to media milling. Unlike the conventional milling techniques, laser fragmentation enabled the treatment of minute amount (as small as several milligrams) of drugs with high efficiency, thus is a useful tool for particle size reduction during the early phases of drug discovery. 相似文献
99.
Scalbert J Meunier FC Daniel C Schuurman Y 《Physical chemistry chemical physics : PCCP》2012,14(7):2159-2163
CO(2) is a major contaminant of renewable H(2) derived from biomass fermentation. The effect of the presence of CO(2) on the activity of alumina-supported Pt and Rh catalysts used for the hydrogenation of toluene at 348 K was investigated. The use of operando diffuse reflectance spectroscopy (DRIFTS) was crucial in unravelling the changes in the nature and abundance of species adsorbed at the sample surface and relating those to the changes of catalytic activity. Rhodium supported on alumina was only partly deactivated by the introduction of CO(2) during the hydrogenation of toluene, contrary to the case of Pt/alumina. Rh was only partially covered by carbonyl species derived from CO(2) and it was shown that toluene could successfully compete with some of the linearly adsorbed carbonyls for adsorption. The alumina support stored many CO(2)-derived adsorbates (carbonates, hydrogenocarbonates, carboxylates) that could spill over to the metal and form carbonyl species even after the removal of CO(2) from the feed. 相似文献
100.
There have been performed experimental measurements of effective thermal conductivity of silica-gel for a stagnant cylindrical fixed bed under transient and steady state conditions in the presence of dry air at different pressures and for different amounts of adsorbed water. The Bauer-Schlünder and Kunii-Smith models have been used to identify the thermal solid conductivity of silica gel pellets from measurements of the conductivity in an adsorbent bed. Sorption rates of water vapor in silica gel were measured using a single-step thermal method by monitoring the sample surface temperature by infrared detection. In order to obtain the mass diffusivity it is necessary to match the numerical solution of the mathematical model to the experimental data. 相似文献